1. Field of the Invention
The subject invention relates to the encoding of video signals enabling the transmission thereof over standard terrestrial and cable broadcast channels.
2. Description of Related Art
Color television signals are currently being transmitted to consumers in accordance with one of several television transmission standards, for example, NTSC and PAL. These standards prescribe various characteristics of the transmission signal, i.e., 525 or 625 scanning lines presented in two consecutive, interlaced fields forming each picture frame at a field rate of 60 (or more precisely 59.94) or 50 Hz, to be transmitted over a transmission channel having a bandwidth of at most 6 MHz.
Over the last few years, there has been increased interest in improving the quality of the received television picture. One of these areas is improving the horizontal and vertical resolution of the television signal. Another area is to change the aspect ratio from a standard ratio of 4:3 to a wide-screen ratio of 16:9. A benefit of this wide-screen ratio is that it is substantially similar to the aspect ratio used in preparing motion pictures. Therefore, it would no longer be necessary to clip side portions of the picture in order to present the same on television. Another of these areas is an improvement in the quality of the audio signal accompanying the transmission.
A common problem in each of the above areas of improvement is that, without special encoding, bandwidth in excess of the above prescribed 6 MHz is required.